ZND-2 Guangya Gel for Oil-Gas Field
Guangya Plugging Agent ZND Series and the matching techniques, is aimed at solving the problems of large loss, loss of return or small return in fracture, cavern or broken zones, and the problems that the bridge plugging or PWD (plugging while drilling) could not solve. The products can effectively and lastingly plug the “thief layer” existing in water flooding reservoir and chemical flooding reservoir, plug deep cracks and broke formation, and stop the underground fluid flowing to the surface.
Application
Profile Controlling, Plugging
ZND-2 Typical Properties
Main components | Watersoluble polymer | |
Appearance | White or Yellowish Particles & Powders | White or Yellowish Particles & Powders |
Particles with Sizes of 0.106 mm-1.180 mm (%) | ≥80.0 | ≥80.0 |
Solid Content (%) | ≥88.0 | ≥88.0 |
Dissolution Time (h) | ≤4.0 | ≤4.0 |
Viscosity (in 12000 mg/L solution) (mPa•s) | 25000 | ≥15000 |
One-minute gel strength (before Aging)(Pa) | ≥15.0 | ≥15.0 |
One-minute gel strength (after Aging)(Pa) | ≥20.0 | ≥20.0 |
ZND-2 offer the following advantages
● Easy to pump due to good shearing thinning properties: It has lower viscosity (e.g. 100-200 mPa·s) at high velocity gradient (e.g. 300-500s-1) and higher viscosity (e.g. 5-10×104 mPa·s or even higher) at low velocity gradient (7.34 s-1)
● Difficult to move again in the porous media after rest
● Reversible super-molecular network gel structure can be formed automatically when the flow rate declines or the sample is on standing, which shows high gel strength and elasticity modulus. In addition, the gel strength and elasticity modulus of ZND-2 will increase with time.
● Able to blend with other solid materials (such as bridging particles, cement, bentonite, etc.) without any influence on its properties.
● No observable damage to the performance of drilling fluid, completion fluid, workover fluid and cementing slurry.
● The non-crosslinked liquid at high concentrations (5000-12000 mg/L) can also be applied in deep profile control to increase recovery, especially in profile modifying and plugging deep serious penetrating bands.
Usage
The product is generally used in plugging after stopping drilling. Prepare 0.8%-1.5% ZND-2 solution, and begin to plug after 2 hours’ dissolving. The amount of liquid varies depending on the well depth and leaking volume. The plugging agent should be injected into the leaking layer as much as possible. Drilling can resume in 24 hours after injection.
Field Cases
ZND-2 has successfully handled leakage and blowout accidents at DaZhou ShuangMiao Well 1# (Dazhou, China), Luojia Well 2# (Kaixian, Chongqing, China), Xushen Platform 8#-Well 1# (Daqing Oilfield, China).
During the operation process, the plugging fluid can automatically stop at a certain depth in the leaking formation, fill in the fissures and limestone caves, and form the “gel plugging slug” that could block up the interior flow of the layer and the flow of wellbore. When the starting pressure difference (generated from the static shear force and elastic resistance) of the slug is greater than the pressure difference between the mud column pressure and formation fluid pressure, the plugging will be successfully achieved.
These successful applications demonstrated that this new self-designed and self-developed Guangya gel has met the design requirements and works very well, and our special plugging technology has achieved satisfactory results for solving leaking problems.
Guangya Gel Plugging Technology
Guangya Gel Plugging Applied in Oilfield